This page used to test IDMFitter.LMFit()
It uses events to calculate function and derivative.
Notice that LM fitter invoked by JavaScript!
Following expression will be fitted:
Y(X)=-0.456*X2+0.00567*X3+200*sin(0.2*X)
Add Math.random()*50

Numeric differentiation
P4: Fix P4

Use Fitting Options

Results: